The present invention relates to a prime mover arrangement comprising an internal combustion engine for driving a first shaft and comprising a steam engine, which is connected to the first shaft by means of a clutch arrangement, for driving a second shaft. Furthermore, a freewheel which interacts with the clutch arrangement is arranged between the first shaft and the second shaft in order to transmit a rotational movement of the second shaft to the first shaft in a first operating mode and to allow the first shaft to freewheel relative to the second shaft in a second operating mode.
The field of application of the present invention encompasses a drive technology of motor vehicles, in particular a drive technology which comprises an internal combustion engine and a steam engine for supporting the internal combustion engine.
When developing internal combustion engines, the reduction of fuel consumption is given a high priority. Internal combustion engines convert a portion of the chemical energy of the fuel into mechanical energy in order to drive motor vehicles. In so doing, a large portion of the chemical energy is released as waste heat which is dissipated in an unused state by means of the cooling system or in the exhaust gas of the internal combustion engine. In order to utilize this thermal energy, it is conceivable for the internal combustion engine to be coupled to a steam engine. The thermal energy from the internal combustion engine is thereby used to generate steam which expands in an expansion machine and thus provides further energy that can be used to drive the vehicle.
A combination of an internal combustion engine and a steam engine for utilizing waste heat is especially suited for use in a commercial vehicle. This is due to the fact that the internal combustion engine has to deliver here a large amount of power and therefore a large amount of thermal energy is available for generating steam.
The generally known prior art discloses a connection of the steam engine to the internal combustion engine via a rigid coupling. As a result, the combustion engine already carries the steam engine along from the start-up of said combustion engine although a sufficient amount of steam pressure is not present for the steam engine. The disadvantage that thereby arises is that the efficiency of the total system is reduced as a function of the friction of the steam engine, specifically when starting the internal combustion engine and as long as the generation of heat by the internal combustion engine is moderate.
The prior art further discloses that the steam engine and the internal combustion engine are connected to one another via an intermediary freewheel. As a result, the internal combustion engine can freely rotate if an insufficient amount of steam pressure is available to the steam engine. In this case, the internal combustion engine therefore does not have to overcome the additional frictional power of the steam engine. The disadvantage of this solution is that the internal combustion engine no longer carries the steam engine along, whereby, in an unfavorable standstill position of the steam engine, said steam engine can possibly no longer start up by itself.
The German patent application DE 10 2010 031 498 A1 discloses an electromagnetic, shiftable clutch which connects a steam engine to an internal combustion engine. In this case, a first shaft can be driven by the steam engine and a second shaft can be driven by the internal combustion engine. In addition, an intermediate wheel is connected to the first shaft and a clutch bell is connected at least indirectly to the second shaft, wherein a freewheel is disposed between the intermediate wheel and the clutch bell. The freewheel performs the task of transmitting the rotational movement of the intermediate wheel connected to the first shaft to the clutch bell and furthermore of allowing the clutch bell to move freely relative to the intermediate wheel. A frictional force or a form fit can at least indirectly be generated between the intermediate wheel and the clutch bell by means of an electromagnetic actuating force which is released by actuating an electromagnet by means of a controller.